Unsteady internal ballistic analysis models of solid and hybrid rocket motors were proposed to study the combustion characteristics of rocket motors. A typical unsteady internal ballistic analysis model was proposed to account for erosive burning with...
Unsteady internal ballistic analysis models of solid and hybrid rocket motors were proposed to study the combustion characteristics of rocket motors. A typical unsteady internal ballistic analysis model was proposed to account for erosive burning with the variance of local velocity and pressure along the grain surface of a solid rocket combustor. To validate the model of concern in the study, both cases of non-erosive and erosive burning were compared with previous researches with marginal accuracy. The effects of combustion pressure, grain length, initial temperature, and vaporization temperature of propellants on the erosive burning was investigated. In this study, the biggest factor affecting the erosive burning is the combustion pressure.
The oxidizer mass flow rate of the hybrid rocket motor accounts for the main flow in the chamber because the mass flow rate of the oxidizer accounts for much more than the fuel. The regression rate of the hybrid rocket can also show the function of the oxidizer mass flow rate. Therefore, the oxidizer mass flow rate is an important factor when considering the combustion characteristics of the hybrid rocket. If the rocket doesn't have the pressurization device, the mass flow rate of the oxidizer isn't constant. Liquid N2O without pressurization devices is chosen as the oxidizer supply system. A hybrid rocket engine that can perform the required propulsion impulse is designed with a time-dependent internal ballistic scheme. The experiment data on pressure in the oxidizer tank was used to predict the change of the oxidizer mass flow rate. The analysis results were evaluated and compared with previous experimental data.
An unsteady internal ballistic analysis model was proposed to account for the variance of local velocity and pressure along the grain surface of a hybrid rocket combustor. The model of concern in the study was fairly comparable with the test result. Combustion efficiencies of test results were valued. The local variation of the oxidizer mass flow rate along the grain surface results in changes to the chamber pressure, regression rate, and gas velocity along its flow direction. The difference of pressure is decreased in inverse proportion to the mass flow rate of the oxidizer. But the difference of pressure is increased in direct proportion to the mass flow rate of the oxidizer if the oxidizer mass flow rate reaches a certain level. The result of this study can account for the oscillation of the chamber. An unsteady internal ballistic analysis model to consider the oscillation of the chamber would be proposed in the future.